1. Field of the Invention
The invention relates to a coupler for corrugated conduits.
2. Description of the Related Art
Many large residential, commercial and office buildings are provided with complex arrays of telecommunication cables. An array of parallel cables is likely to extend from a main junction box in a building and will traverse interior walls, ceilings and/or floors of the building to specified locations where the cables can be accessed. Small trunks of cables are likely to be branched or spliced from a main trunk of cables to direct the smaller trunk of cables towards a particular floor of a building or a particular area on a floor. Individual cables then may be branched or spliced from the small trunks of cables.
Cables often must be bent to accommodate required changes of direction. However, very abrupt bends of a cable can create stresses on the outer curvature of the bend. Such stresses can stretch and damage the insulation coating on the outside of a cable and can damage the shielding layers provided on many cables. Corrugated conduits protect cables and help to ensure smooth bends. Plastic corrugated conduits can be manufactured inexpensively and provide a very good strength-to-weight ratio. Additionally corrugated conduits exhibit sufficient flexibility to facilitate both storage, transportation and installation. Couplers are available for joining corrugated conduits in end-to-end relationship. Examples of such couplers are shown, for example, in U.S. Pat. Nos. 4,168,091, 4,273,367, 4,443,031, 4,647,074, 4,795,197, 5,015,013, 5,458,380, 6,145,896, 6,398,270 and 6,595,473.
Corrugated conduits are not well suited to the branching or splicing that often is required for telecommunication cables. As a result, installers often use hand tools, such as cutting pliers, snips or knives to make a hole in a corrugated conduit. The required number of telecommunication cables then are directed from the main trunk and through the hole. The hole formed in a corrugated tube in this manner typically provides a sharp edge that can damage the cable. Additionally, an installer is likely to bend the branched cable or cables sharply at the hole, thereby creating stresses and strains, particularly along the outer edge of the bend. The branched cables may be passed through another conduit. However, there often is a space between the conduit for the main trunk of cables and the conduit for the branched cables. Regions of the branched cables between the hole in the main conduit and the end of the branch conduit are exposed and may be subject to damage. Additionally, the process of cutting a hole in the side of a conduit is labor intensive, time consuming and creates the potential for damaging cables during the cutting process.
Connectors are available for more than two opposed corrugated tubes. For example, U.S. Pat. No. 5,046,766 shows a connector for two corrugated tubes disposed in axially aligned and end-to-end relationship and one corrugated tube that extends at a right angle to the aligned tubes. This connector, however, requires the cables to be bent at a sharp right angle through the connector. As explained above, a sharp right angle bend generally is not desired. U.S. Pat. No. 5,272,459 shows a Y-connector that permits two corrugated tubes to extend from the wall of a junction box or the like. The Y-shaped coupler has two separate halves that can be placed over one another and around the two corrugated tubes. A non-corrugated portion of the coupler then is passed through an aperture in the wall and is secured to the wall by a nut or similar fixturing device.
It is an object of the subject invention to provide a coupler that enables a corrugated tube to be branched efficiently from axially aligned corrugated tubes.
It is another object of the subject invention to provide a coupler that can be molded efficiently and that reduces the assembly of parts required at the installation site.